Status of glycemic excursions and hypoglycemia in patients with type 1 diabetes 2 months after first initiation of intermittently scanned continuous glucose monitoring: a pilot study

Objective To investigate glycemic excursions and changes in time in hypoglycemia (hyT) in Japanese type 1 diabetes (T1D) patients 2 months after the first initiation of intermittently scanned continuous glucose monitoring (isCGM). Methods We enrolled 15 adult T1D patients on insulin therapy to evaluate changes in the parameters for glycemic excursions 2 months after initiating isCGM by using the Wilcoxon signed-rank test. Binomial logistic regression analyses were also used to identify predictors of hypoglycemia. Results A total of 14 patients were available for analysis. Median HbA1c decreased significantly from 7.6% (interquartile range, 6.9–8.3%) to 7.2% (6.7–7.8%) ( P = 0.047). Mean glucose, standard deviation of glucose, time in range, and time above range were not significantly different from baseline, while time below range (from 2.2 [1.0–6.9] to 5.0 [2.0–10.8]%; P = 0.016), hyT (from 26.8 [14.5–75.5] to 56.8 [21.7–110.9] min/day; P = 0.030), and time in severe hypoglycemia (shT, from 4.3 [0.0–8.9] to 11.0 [0.0–24.3] min/day; P = 0.022) increased significantly. Additionally, shT increased significantly only during daytime. The factor associated with hyT was found to be the reduction in total insulin dose after 2 months. Conclusions In T1D patients with a median HbA1c of 7.6%, HbA1c was significantly decreased 2 months after initiating isCGM, while hyT increased, particularly during daytime. Study results suggest that a reduction in the total insulin dose of about 0.10 U/kg may be required in some cases. These findings need to be taken into account when initiating isCGM.